I built this device in 1989 as part of the Electricity/Electronics exhibit
at the Museum of Science in Boston. Each small light is controlled by an
e-field sensor, and will respond to any "static electricity" in the area.
When a negatively-charged object approaches the glowing red panel, the
lights nearest the object will turn off. If you scuff your shoes on the
rug and then wave your hand around the panel, a big black blotch will
follow your hand. This "blotch" is a crude image of the electrical field
surrounding your body. Touch a grounded object, and your hand no longer
will affect the panel. Rub a balloon on your head in order to charge it,
and the balloon will affect the panel from several feet away.